6.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Marek Vasut marex@denx.de
[ Upstream commit 172695f145fb4798ab605e8a73f6e87711930124 ]
In case the LCDIF is enabled in DT but unused, the clocks used by the LCDIF are not enabled. Those clocks may even have a use count of 0 in case there are no other users of those clocks. This can happen e.g. in case the LCDIF drives HDMI bridge which has no panel plugged into the HDMI connector.
Do not attempt to disable clocks in the suspend callback and re-enable clocks in the resume callback unless the LCDIF is enabled and was in use before the system entered suspend, otherwise the driver might end up trying to disable clocks which are already disabled with use count 0, and would trigger a warning from clock core about this condition.
Note that the lcdif_rpm_suspend() and lcdif_rpm_resume() functions internally perform the clocks disable and enable operations and act as runtime PM hooks too.
Reviewed-by: Liu Ying victor.liu@nxp.com Fixes: 9db35bb349a0 ("drm: lcdif: Add support for i.MX8MP LCDIF variant") Signed-off-by: Marek Vasut marex@denx.de Link: https://patchwork.freedesktop.org/patch/msgid/20240226082644.32603-1-marex@d... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/mxsfb/lcdif_drv.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/mxsfb/lcdif_drv.c b/drivers/gpu/drm/mxsfb/lcdif_drv.c index ea10bf81582e9..0f895b8a99d62 100644 --- a/drivers/gpu/drm/mxsfb/lcdif_drv.c +++ b/drivers/gpu/drm/mxsfb/lcdif_drv.c @@ -343,6 +343,9 @@ static int __maybe_unused lcdif_suspend(struct device *dev) if (ret) return ret;
+ if (pm_runtime_suspended(dev)) + return 0; + return lcdif_rpm_suspend(dev); }
@@ -350,7 +353,8 @@ static int __maybe_unused lcdif_resume(struct device *dev) { struct drm_device *drm = dev_get_drvdata(dev);
- lcdif_rpm_resume(dev); + if (!pm_runtime_suspended(dev)) + lcdif_rpm_resume(dev);
return drm_mode_config_helper_resume(drm); }